Acyloxysilanes and acyloxysiloxanes are well known and have been prepared heretofore by reacting in a column at an elevated temperature, a chlorosilane and an aliphatic carboxylic acid. U.S. Pat. No. 3,974,198 to Ashby discloses an improved process for preparing acyloxysilanes by reacting a chlorosilane with a carboxylic acid or carboxylic acid anhydride in the presence of an iron complexing agent. In comparison to the process disclosed in U.S. Pat. No. 3,974,198, the process of this invention can be carried out in the absence of iron or iron complexing agents. In addition, the process of this invention can be conducted in the absence of expensive solvents and with a very short reaction time. Moreover, excellent yields of acyloxysilanes are obtained having a very low concentration of acyloxysiloxanes. Also, acyloxysiloxanes prepared in accordance with the process of this invention have the advantage that they are not contaminated with iron compounds which have a tendency to impart discolorations thereto.
A process is also described in Chemical Abstracts, Volume 77, 1972, page 70, (153525q) for preparing acyloxysiloxanes which comprises partially hydrolyzing acyloxysilanes in the presence of tetrahydrofuran. In contrast to the process described in Chemical Abstracts, the process of this invention has the advantage that it does not require the use of tetrahydrofuran and it does not require the preparation of the acyloxysilane in a separate step prior to the formation of the acyloxysiloxanes.
Therefore it is an object of the present invention to provide an improved process for preparing acyloxysilanes. Another object of this invention is to provide an improved process for preparing acyloxysiloxanes. Still another object of this invention is to provide an improved process for preparing acyloxysilanes and acyloxysiloxanes in the absence of organic solvents. A further object of this invention is to provide an improved process for preparing acyloxysiloxanes in a single step from chlorosilanes and carboxylic acids. A still further object of this invention is to provide an improved process for preparing acyloxysilanes and acyloxysiloxanes in the absence of iron and iron complexing agents.